Tesis sobre el tema "Production scrap"

Rare earth metals are at highest supply risk of all metals for clean technologies due to supply restrictions. Rare earth elements are essential for the highest energy permanent magnets which are used in high-tech green applications such as wind turbines and electric motors. This rare earth 'crisis' has been addressed by many authors by reducing or substituting the rare earths for less critical elements. The focus of this thesis, however, is on recycling of rare earth magnetic materials. Previous work has been focused on recycling NdFeB by re-sintering and blending alloying elements to improve the final magnetic properties. However, none of these studies have addressed the systematic addition of alloying elements or the particle size effect on the final magnetic performance of the recycled magnet. The work in this thesis is aimed at maximising the magnetic performance of recycled NdFeB magnets by investigating the effect of the manufacturing route and the influence of adding alloying elements. Uncoated end-of-life sintered NdFeB were exposed to hydrogen at room temperature to break them down into a friable powder; which was then milled, sieved, aligned, pressed and sintered into recycled magnets. The resulting magnets were tested on a permeameter at room temperature, 75 and 150oc to measure the magnetic properties. Scanning electron microscopy was used to assess the microstructures. Mechanical properties such as Vickers hardness and fracture toughness were also studied.

This study intends to better control the final composition of steel by trying to have a better knowledge of elements including copper, nickel, molybdenum, manganese, tin and chromium in the scrap. This objective was approached by applying probability and statistical concepts such as normal distribution, multiple linear regression and least square and non-negative least square concepts. The study was performed on the raw materials’ information of Ovako Smedjebacken and Ovako Hofors, two steel production plants in Sweden. The information included but were not limited to the amount of the different scrap types used in the charge, total weight of the charge and the final composition of the produced steel.  First, the concept of normal distribution was used as to consider the variations of the alloying elements between the estimated and measured alloy contents. The data were then used to consider a model for distribution factor of the studied elements. Also, an estimation of the alloy contents in the scrap type given the final steel composition was carried out using the concept of probability and statistics. At the end, a comparison of the results from the different concepts was done.

Les pneus de caoutchouc usagés sont l'une des plus grandes productions annuelles de déchets dans le monde entier. Ceci est dû à leur composition non biodégradable, leur durée de vie et leur traitement difficile, ce qui provoque des problèmes environnementaux et de santé publique, en raison de son accumulation et de la mise en œuvre de techniques de traitement inappropriées. En tenant compte de ce problème, il est envisageable de chercher à valoriser ces déchets grâce à des procédés comme la pyrolyse. L'objectif principal de ce travail était d'évaluer expérimentalement la pyrolyse de pneus du caoutchouc (STR) dans le but de produire des composés aromatiques monocycliques. Pour cela, une étude expérimentale de pyrolyse de STR sans catalyseur a été réalisée et les conditions les plus favorables de température et de débit d'azote ont été déterminées. La transformation du D,L limonène présent dans l’huile en aromatiques en utilisant différentes combinaisons hétéropolyacide/support ont été évaluées, afin de sélectionner les plus sélectives vers les aromatiques. Les résultats ont montré une conversion du limonène en p-cymène, monoterpènes et menthènes, et on a constaté que la production de p-cymène est promu par l'acidité de Lewis. Depuis, les catalyseurs étant plus sélectifs dans la transformation du limonène, ont été validés dans la pyrolyse de STR. Les résultats montrent que le rendement en aromatiques a augmenté (de 8,05%) à un maximum de 15,06 %p et la concentration a abouti environ 37%, en utilisant un catalyseur à base de molybdène dans lequel les sites d'acide de Lewis sont les prédominants
Scrap tire are waste that produces one of the largest annual production all over the world. Because its non-biodegradable composition, its end of life and treatment is difficult, causing environmental and public health problems, due to the accumulation and implementation of inappropriate treatment techniques. Based on this problem it is conceivable to seek to valorise these wastes through processes such as pyrolysis. The main objective of this work was to evaluate experimentally the pyrolysis of scrap tire rubber (STR) in order to improve single ring aromatic compounds, which have a higher industrial value in the oil of STR pyrolysis. To this end, an experimental study of pyrolysis of STR without catalyst was carried out and the most favorable temperature and nitrogen conditions were determined. The transformation of D, L limonene present in the oil into aromatics using different heteropolyacid / carrier combinations was evaluated, in order to select the most selective towards the aromatics. The results showed a conversion of limonene to p-cymene, monoterpenes and menthenes, and it was found that the production of p-cymene was promoted by Lewis acidity. Since the catalysts are more selective in the transformation of limonene, have been validated in the pyrolysis of STR. The results show that the yield of aromatics has increased (from 8.05%) to a maximum of 15.06% p and the concentration about 37%p, using a molybdenum catalyst in which the acid sites of Lewis are the predominant

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.
The Peruvian export supply is primarily based on the segment of dressings and condiments. This paper seeks to adapt lean manufacturing tools using Poka-Yoke techniques and process standardization, which may align with existing processes to prevent production errors. This combination of tools is expected to reduce the percentage of waste generated throughout the condiment production process. Subsequent to an initial evaluation of the current method combined with the application of both the tools, 11.4% waste reduction was ultimately reported.
Revisión por pares

The Study aims to evaluate what kind of systems buyers of raw materials use for handling the flow of information in their supply chain of raw materials. Due to the complexity of the topic, the Study is only examining the continuous exchange of information between suppliers and buyers of raw materials. The purpose of the Study is to provide recommendations to Boliden on which system is suitable for implementation at the company. The Study’s results were achieved by collecting both primary and secondary data. The primary data was collected through interviews with raw materials buyers and trade organisations. A total of fifteen interviews were conducted in the Study. The secondary data was collected through a literature study. The results of the Study indicate that there exists four different solutions for managing the flow of information in a supply chain of raw materials. The most common solution among buyers of raw materials is to use the so-called “traditional” systems, i.e. e-mail, telephone and physical meetings. The second most common solution is to use an external information handling system provided by a trade organisation. The third most common solution is to use a commercial information handling system, i.e. a system provided by a commercial provider. Lastly, the least common solution is to develop an information handling system on its own, i.e. a proprietary information handling system. The conclusion of the Study is that Boliden should use two information handling system simultaneously, i.e. an external information handling system and the traditional information handling systems. However, Boliden should also look into the option of developing a proprietary information handling system.

Les batteries lithium-ion (LIB) ont révolutionné l'électronique portable et se sont étendues au secteur de la mobilité grâce aux progrès des matériaux d'électrodes, des électrolytes et des processus de production. Cependant, la demande croissante de LIB pose des défis mondiaux en matière de gestion des déchets. En tant que ressources critiques, les matériaux LIB nécessitent un recyclage efficace dans le contexte de l'économie circulaire tout en répondant aux objectifs de durabilité et de neutralité carbone. Les méthodes de recyclage conventionnelles, telles que la pyrométallurgie et l'hydrométallurgie, ne parviennent pas à récupérer entièrement les composants LIB, en particulier lorsque des déchets de production - un nouveau flux de déchets vierges - apparaissent. Le recyclage direct, une stratégie nouvelle et efficace, préserve les propriétés des matériaux telles que la composition, la structure et les propriétés, améliorant ainsi les taux de récupération. Cette thèse explore le recyclage direct des déchets de production et évalue le potentiel de recyclage des cellules 18650 usagées à différents niveaux de dégradation. Un nouveau procédé à base de CO2 a été développé pour le recyclage direct des déchets de production d'électrodes LIB. En utilisant un mélange de solvants de phosphate de triéthyle, d'acétone et de CO2, la dissolution du liant a été améliorée et la délamination des matériaux d'électrode positive a été accélérée, séparant efficacement LiNi0,6Mn0,2Co0,2O2 (NMC622) du collecteur de courant. L'étude explore également la dégradation dans les cellules 18650 avec cathode NMC622, anode en graphite et électrolyte à base d'EC sous divers protocoles de vieillissement, révélant des changements de matériaux importants, notamment la perte de Li, la décomposition de l'électrolyte et la migration du Mn. Le CO2 liquide et l'acétonitrile ont été utilisés pour extraire les carbonates et les produits de dégradation liquides, tandis que le carbonate de diméthyle comme cosolvant avec le CO2 liquide a permis une récupération élevée du lithium. Ces résultats fournissent des informations précieuses sur le vieillissement des batteries et mettent en évidence les défis d'un recyclage direct efficace, soulignant la nécessité de stratégies innovantes pour faire face à ces processus de dégradation complexes
Lithium-ion batteries (LIBs) have revolutionized portable electronics and expanded into the mobility sector through advancements in electrode materials, electrolytes, and production processes. However, the growing LIB demand poses global waste management challenges. As critical resources, LIB materials require efficient recycling within the context of circular economy while meeting sustainability and carbon-neutrality goals. Conventional recycling methods, such as pyrometallurgy and hydrometallurgy, fall short in fully recovering LIB components, particularly as production scraps—a new, pristine waste stream—emerge. Direct recycling, a novel and efficient strategy, preserves material properties such as composition, structure, and properties, improving the recovery rates. This dissertation explores direct recycling of production scraps and evaluate spent 18650 cells their recycling potential across varying levels of degradation. A novel CO2-based process was developed for the direct recycling of LIB electrode production scrap. Using a solvent mixture of triethyl phosphate, acetone, and CO2, binder dissolution was enhanced and the delamination of positive electrode materials was accelerated, efficiently separating LiNi0.6Mn0.2Co0.2O2 (NMC622) from the current collector. The study also explores the degradation in 18650 cells with NMC622 cathode, graphite anode, and EC-based electrolyte under various ageing protocols, revealing significant material changes, including Li loss, electrolyte decomposition, and Mn migration. Liquid CO2 and acetonitrile were used to extract carbonates and liquid degradation products, while dimethyl carbonate as a cosolvent with liquid CO2 allowed high lithium recovery. These findings provide valuable insights into battery aging and highlight challenges for effective direct recycling, emphasizing the need for innovative strategies to address this complex degradation processes

Riassunto La sopravvivenza delle numerose imprese piccole e molto piccole che caratterizzano il contesto agricolo italiano, dipende dalla loro capacità di differenziare la loro produzione e dalla propensione al rivolgersi verso nuove forme di reddito, come i mercati contadini e il commercio in rete. Certamente la Legge Finanziaria del 2007 ha dato un vigoroso impulso a tutto ciò che gravita intorno alla filiera corta in ambito agroalimentare. Questo tipo di orientamento tuttavia presuppone dei cambiamenti strutturali nelle aziende. Una tale metamorfosi riguarda in primo piano anche la dotazione impiantistica e la capacità di utilizzarla. Da uno studio condotto dal progetto MIERI, il mercato di impianti per la produzione industriale di cibo presenta una scarsissima offerta di apparecchiature di piccole dimensioni. Esiste quindi una profonda mancanza di soluzioni tecnologiche compatibili con le esigenze delle aziende che vorrebbero entrare nei promettenti circuiti commerciali legati alla circolazione di alimenti trasformati in un contesto di filiera corta. Inoltre la moderna industria è costantemente alla ricerca di nuovi percorsi finalizzati alla nascita di prodotti innovativi. Quindi, sempre più spesso, l’attenzione degli sviluppatori di nuovi prodotti è rivolta alla loro naturalità e salubrità. In un tale ambito i piccoli produttori sono svantaggiati per molte ragioni, in special modo per problemi di sicurezza alimentare e da mancanza di tecnologia Recentemente la ricerca alimentare relativa agli impianti sta lavorando nella direzione dei piccoli produttori artigianali. È infatti ora possibile avere accesso a soluzioni impiantistiche capaci di combinare: la qualità e la sicurezza alimentare, tipici della grande industria con l’altissima qualità delle materie prime che caratterizza molti produttori artigianali, inoltre risolvendo molti dei problemi legati a sicurezza, tecnologia, logistica e, accessibilità tipici di molti piccoli produttori. Negli ultimi anni l’attenzione all’uso di energie alternative e alla riduzione di scarti e sprechi, volti nella direzione di una produzione più sostenibile, è diventato un tema globale. Le piccole e piccolissime produzioni industriali hanno le caratteristiche, diversamente dalla grande industria, per poter inserire nei loro cicli produttivi l’impiego di energie rinnovabili e di operare un’attenta politica di riduzione di scarti e sprechi. Questo studio si è occupato in primo luogo di sviluppare una serie di prodotti alimentari tenendo conto di quanto detto finora e cioè: legame col territorio, tradizioni locali, qualità e sicurezza alimentare, impiego di energie alternative. In secondo luogo lo studio tratta la verifica da un punto di vista biochimico e sensoriale della qualità degli alimenti sviluppati. In ultima analisi viene fatto un bilancio energetico relativo alle produzioni che consentono l’uso di energie alternative. Durante il presente lavoro di dottorato sono stati sviluppati 14 prodotti: 4 tipi di marmellata, 1 dolcificante multifunzionale, 3 prodotti essiccati, 5 tipi di yogurt, 1 tipo di caramella di frutta. Per il loro sviluppo sono stati impiegati due impianti prototipo: una linea di trasformazione polifunzionale miniaturizzata ed un essiccatore ad energia solare. Per ogni prodotto sviluppato è stato seguito il comportamento di uno o più marker di processo (molecole termicamente instabili considerate importanti da un punto di vista nutrizionale e che sono naturalmente presenti nelle materie prime). Nella maggior parte dei prodotti sono stati ottenuti buoni risultati con i test sensoriali ed è stata osservata una considerevole ritenzione dei marker di processo, confermando quindi la buona qualità dei prodotti sviluppati. Il livello di ritenzione dei marker varia in funzione del prodotto specifico e dei trattamenti tecnologici utilizzati. Anche l’analisi sensoriale, dove eseguita, ha dato risultati che rispecchiano un alto gradimento dei prodotti testati. Le prove realizzate col fine di valutare l’uso di energie alternative per la produzione di alimenti o semilavorati hanno dato risultati nettamente positivi, nonostante, in alcuni casi, le condizioni sperimentali e impiantistiche si siano rilevate limitanti.
Abstract The survival of many small and very small businesses that characterize the Italian agricultural context, depends on their ability to differentiate their products and the propensity to turn toward new forms of income, such as farmers' markets and network trade. Certainly the Italy’s Finance Act of 2007 gave a powerful boost to everything that revolves around the short supply chain in agro-food sector. Such a change, however, requires structural changes in companies indeed. The consequent metamorphosis also relates with the company technological facilities and the ability to use it. A study conducted by the project MIERI, shows that the equipment's market for food industrial production offers a very narrow range of small size equipments. Enterprises who would like to enter the promising markets connected to the processed food trade in the context of a short chain cannot easily find, on the facilities market, technological solutions consistent with their needs. Modern food industry is constantly looking for new paths in order to obtain original products. More and more often the attention during their development is focused on their healthiness and naturalness. In this context small producers are penalized due to several reasons, mostly depending on food safety and a lack of technology. Recently, research on small food processing plants is giving new tools to small and craft producers. It is now possible to combine food safety and quality, typical of big factory, with high quality raw materials, typical at many craft producer, thus solving many typical problems of craft producers, related to food security, technology, logistics and accessibility. In recent years the focus on the implementation of alternative energy sources use and the reduction of scrap and waste, aimed in the direction of a more sustainable production, has become a global issue. Unlike big industry, small and very small producers own the characteristics to include in their production cycles both the use of renewable energy and the option to operate careful policies aimed to a real reduction of scrap and waste. This study focused firstly on developing a number of food products, taking into account the above, namely: link with the territory, local traditions, food quality and safety, use of alternative energy. Secondly, the study focused on the verification both by a biochemical and a sensory point of view of the developed foods quality. As final analysis is carried out an energy balance concerning the productions that allow the use of alternative energies. During this study were developed 14 products: 4 types of marmalade, 1 multifunctional sugar substitute, 3 dried products, 5 types of yogurt, 1 type of fruit candy. Their study and production took place by means of two prototype systems: a miniaturized processing line and a solar drier system. For each product type was followed the behavior of one or more process biochemical markers (thermally unstable molecules considered important from the nutritional point of view). In most of the products developed were obtained good results in sensory tests and was observed a considerable retention of the quality processing markers thus both confirming the good quality of the products developed. The markers retention varies according to the specific product and the technological treatments used. Moreover, sensory analysis, gave results that reflect a high overall liking of the products tested (where performed). The trials performed with the aim to evaluate the use of alternative energy sources for the production of foods or semi-finished products gave clearly positive results, despite, in some cases, the experimental and plant conditions have been observed as limiting.

碩士
朝陽科技大學
工業工程與管理系
107
This study explores the optimal common cycle and delivery policy for a multi-item production system with adjustable production rate and scrap; and the optimal production cycle for a system with random breakdown, scrap and adjustable production rates. Traditional economic production quantity (EPQ) assumed a perfect production process with no breakdown occurrences and no defects, fixed production rate, and continuous delivery plan. However, the assumption of EPQ model is too simple to fit the needs of real life situations. In order to cope with the real production situations, the proposed model 1 studies the optimal common cycle for multi-item production systems with all of defective items are scrapped and considering two types of delivery plans. One is a continuous and the other is a multiple delivery. Also, with the purpose of reducing production completion time and/or machine utilization, the manufacturing firms may adjust production rate or increase the workers’ hours. Therefore, we look into the effect of variations in adjusted rates on system’s optimal policy and various cost components. The proposed model 2 explores the optimal production cycle for a fabrication system with adjusted rate, scraps, and random breakdown under the abort/resume (AR) policy and scraps. The AR policy means that the machine continues to produce unfinished batches when it has been completely repaired. Finally, numerical examples were used to show applicability and sensitivity analyses for these two models.

碩士
朝陽科技大學
工業工程與管理系碩士班
93
This study proposes an algebraic method for solving imperfect quality economic production quantity (EPQ) model. It includes the following two subjects: (1) the EPQ model with random scrap items and shortages are permitted and backordered; (2) the EPQ model with random scrap items and no shortages are allowed. Algebraic derivations are used in each case, in order to obtain the optimal production operating policies that minimize the overall production-inventory costs. Traditional approaches for deriving optimal production lot size are by using the differential calculus on the production-inventory cost function with the need to prove optimality first. Recent articles proposed the algebraic approach to the solution of classic economic order quantity (EOQ) and economic production quantity (EPQ) model without reference to the use of derivatives. This paper extends it to a finite production rate model taking the backlogging and random scrap rate into consideration. This study demonstrates that optimal production lot size for the aforementioned model can be derived algebraically and the expected overall production-inventory costs can be obtained immediately as well. The results of this thesis are verified with prior works of the same models and when scrap rate equals to zero, it is identical to the optimal lot-size equations given by the classic EPQ models. Numerical examples demonstrate their practical usages.

碩士
國立臺北科技大學
工業工程與管理系EMBA班
105
The average defect rate of an automatic soldering equipment is 8.84% in D company, and the improvement goal is to lower the defect rate to 1.5% and below. This study applies the five improvement stages of Six Sigma methods (Define - Measure - Analyze - Improve – Control, D-M-A-I-C) to achieve this goal. The first stage is to define the project scope, the dependent variables (Y, y), and the defects. In the “Measure” stage, MSA is firstly used to confirm the effectiveness of the measurement system, and to ensure the stability of the production process. Then, analysis methods such as the process mapping, cause and effect matrix, Plato plot, the 8020 Rule are used to find those possible factors that cause defects. Through the process failure mode effects analysis, five quick improvement measures were taken to reduce the process defect rate to an average of 2.66%. Three un-improved factors, x1: tin wire length, x2: soldering iron temperature, x3: welding time, were left for the next “Analyze” stage. By using experimental design method, it is confirmed that x1, x2 and x3 are key factors that have significant effect on Y. In the “Improvement” stage, parametric analysis and optimization were carried out by using Response Surface Methodology to obtain the best parameters of x1 = 3.0 cm, x2 = 403.0 ℃ and x3 = 4.6 sec. In the “Control” stage, the improvement achievement are monitored to ensure consistently maintaining at a defect rate of ≦1.5%. Then the x key factors, Y and y are controlled by the statistical process control to ensure the improvement result. Finally, the estimated financial savings of this improvement project is about 1,880.5 USD/month.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Masters of Science in Engineering. Johannesburg, 2017
This dissertation presents the zinc recycling of tool grade cemented tungsten scrap material generated during commercial production at Pilot Tools Pty Ltd (South Africa), production of powders and alloys from the zinc recycled materials, and evaluation of the properties of the recycled and un-recycled powders and alloys. Tool grade cemented tungsten carbide inserts were subjected to the zinc recycled process under controlled conditions. Tungsten carbide, cubic (TiC, TaC, NbC, TiCN) carbides and Co were recovered from the recycled scrap material. Two recycled alloys, R and RA, and two un-recycled alloys NS and N were produced following the conventional powder metallurgy route. Alloy R was made from 100 % zinc recycled powder with stoichiometric adjustment of C only, and alloy RA was made from 100% zinc recycled powder with stoichiometric adjustment of C and Co. Alloy N was produced under the same conditions as the recycled alloys R and RA, while alloy NS was produced at commercial level at Pilot Tools Pty Ltd (South Africa) using un-recycled powders. The alloy properties were evaluated following standard procedures for hardmetals. When the zinc recycled material was mechanically disintegrated, about 70 % of the recycled material was recovered as fine powder, while 30% was recovered as coarse oversize particles. The oversize particles were quite tough due to a high Co content, and it was difficult to disintegrate them through milling or repeated zinc recycling. The recycled powders took twice as much time to mill to the desired size as the new un-recycled powders, and had predominantly angular particles, while the new powders had smaller more rounded particles. A cubic free layer (CFL) was formed in all the alloys during sintering, although the recycled alloys R and RA had a narrower CFL compared to the new alloys NS and N. The recycled alloys R and RA had carbide grain size, carbide contiguity, binder mean free path, hardness, fracture toughness and wear rate which were generally within the same ranges as the new un-recycled alloys.
MT2018

博士
中原大學
工業與系統工程研究所
99
In this research, we consider the imperfect production processes of the Economic Lot Scheduling Problem (ELSP) which deals with multi-product produced on a single production facility. The basic assumption of the classical ELSP model is that the production process is perfect. In fact, this assumption may not be valid for most of the manufacturing environments. Owing to aging, many production processes may deteriorate to produce defective products. Due to imperfect production processes, decisions regarding whether and when to implement a screening process are typical of every inventory problem. Besides, rework of defective products, which may eliminate waste, reduce disposal costs and comply with environmental legislation, is also an important topic. This research is concerned with the joint effect of scrap, imperfect repair, and shortage on the ELSP involving three types of screening processes with or without rework considerations. In general, a production facility is assumed to be in control at the start of a production run. Owing to aging, it may deteriorate and shift at a random time to an out-of-control state, and consequently produces a fixed fraction of nonconforming items. There are two situations to handle the defects in this research: (1) these defective items cannot be repaired or reworked, and thus must be scrapped with an additional cost; (2) some proportion of defective items cannot be reworked and must be scrapped. The rest of these defective items can be reworked off line. However, since the repair process is imperfect, scraps are produced during the manufacturing and/or rework processes. In the first situation, three models are presented to consider whether and when to implement a screening process, which are: (1a) no screening process, (1b) after-production screening, and (1c) in-production screening. On the other hand, there are several models are proposed in the second situation with various screening options that are (2a) under no screening process with repair before/after depletion, (2b) after-production screening with repair right after screening, and (2c) in-production screening with repair right after production. In this research, a Common Cycle (CC) approach is applied to solve ELSP under imperfect production process. The objective is to determine an optimal common production cycle time that minimizes the expected total cost per unit of time. A solution procedure is developed to find near-optimal solutions for the models. By approximating exponential functions included in the objective functions, certain closed-form solutions can be developed. A genetic algorithm heuristic is implemented to verify the effectiveness of the solution procedure we proposed in this dissertation. Numerical examples are presented to illustrate the derivation of the optimal common production cycle time. These results show apparently that the less reliable a production process is, the shorter a production common cycle time should be. Without rework considerations, strategy without screening is properly adopted when the process is reliable. As the process becomes less reliable, after-production screening process is implemented. On the other hand, with rework considerations, strategy without screening is properly adopted.

碩士
朝陽科技大學
工業工程與管理系碩士班
99
Products are going exquisite nowadays, so a production with small amount of diversification is requested. This study reviews the delivery system of various products for many times. To evaluate the strategy to know what amount the production by batch and what way the delivery in order to reach the optimum. In the case study regarding the type of traditional inventory management, Conventional assumption is the indefectible production and one time delivery. So there are a lot of differences between traditional inventory model and practical conditions. It is impossible to produce goods without any defected in reality. To deliver all the done goods continuously is not always true and practical. The different way to produce and deliver goods is requested by various products in this study. Under the consideration of pursuiting the lowest and best total cost. There are different ways to products and delivery. This research focuses on the study of producing the various goods by batch and delivering the goods separately to meet customer’s need. We will recommend and build up the analysis model by way of mathematics. The model includes the stock cost of manufacturing and customer’s site, and the objective is to derive the best production lot and the best production cycle. Practice examples are provided to demonstrate usages of research result, which should become good reference for practitioners in making such a decision.

碩士
國立高雄應用科技大學
工業工程與管理系
99
The scrap tyre derivative environment and hygiene problem has become more serious. Pyrolysis is currently most advanced technique to regenerate the related material from scrape tyres. Once decomposition the Combustible Pyrolysis Gases, Steel cords, Pyrolysis Oil and Pyrolytic Carbon Black – CBp can be generated from waste tyres, which in this case combustible pyrolysis gases can take as reaction chamber and boilers auxiliary fuel, steel cords can be sold as recycling waste steel, and pyrolysis oil can be used as fuel oil after distillation, desulfurization, bleaching and deodorizing. CBp could be reproduced as high reinforced carbon materials after purification, which can be applied to green tires, anti-vibration pads, rubber and plastic adjunction, and etc. After activation CBp could be reproduced as porous carbonaceous materials which can be applied to capacitance activated, carbon, medicines, cosmetics, and etc. Through modification it could be reproduced as electronic-ink carbon materials applying to inkjet ink, photocopy toner, conductive adhesive, electronic components, and etc. It also could be reproduced as carbon nanomaterial through grinding and applying to Nano Catalyst, nanofiber, magnetic conductor, and etc. CBp might be the most valuable recycled product to commercialize as its features similar as commercial carbon black products, however, it has lower purity, over average ash content and lower market value, since part of chars and oil was remained while pyrolysis, it can only being apply to low rubber filling generally. Instead of amounts of effectiveness studies and R&Ds being appeared in the market, how to take client oriented as priority, providing required products must be the top issue for pyrolytic recycling firms. Through the efficient and systemically recycle procedure, the raw material can be recycled, moreover, the nature of scrape tyre materials can be changed into higher-performance material. This can efficacious reduce the impact of environment, inspire higher benefit, apply traditional industry into new material aspect. Reduc the impact of scrape tyres to environment not only can spur the business of renewable energy, correspond to international green industry, and also create the sustainable environment. Key Words: Waste Tire, Pyrolysis, Pyrolytic Carbon Black - CBp

碩士
朝陽科技大學
工業工程與管理系碩士班
101
This study considers the integration of (n +1) delivery policy in production of a single product with the random machine breakdown, and imperfect production completely scrapped. Imperfect production process is assumed, there will be defective products and are completely scrapped, and the machines in the production process is subject to breakdown randomly. EPQ model assumes continuous delivery deviates from the actual situation is different. This study is more in line with reality manufacturing continuous distribution by assuming multiple deliveries. This study develops a mathematical model for a production system with stochastic machines breakdown, under AR (abort / resume) policy, when the machine breakdowns, it is under repair immediately, after repair it continues to complete the production of unfinished lot. The optimal production time is derived in this study. Finally, numerical example with sensitivity analyses are given to demonstrate practical usages of our obtained results.

Includes bibliographical references (leaves G-1-G-11 ).
vii, 1 v. (various pagings) : ill. (some col.) ; 30 cm.
Substatial developmental work is required to acheive economically attractive poly-hydroxyalkanoate (PHA) production. Aims to improve the understanding of PHA production by recombinant Escherichia coli, with a view to guiding future developmental work. Also suggests numerous areas where further improvements to PHB production are possible, and proposes ways in which they could be implemented.
Thesis (Ph.D.) -- University of Adelaide, Dept. of Chemical Engineering, 2001

Includes bibliographical references (leaves G-1-G-11 ).
vii, 1 v. (various pagings) : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Substatial developmental work is required to acheive economically attractive poly-hydroxyalkanoate (PHA) production. Aims to improve the understanding of PHA production by recombinant Escherichia coli, with a view to guiding future developmental work. Also suggests numerous areas where further improvements to PHB production are possible, and proposes ways in which they could be implemented.
Thesis (Ph.D.)--Adelaide University, Dept. of Chemical Engineering, 2001

碩士
朝陽科技大學
工業工程與管理系碩士班
100
This thesis studie the optimal production-delivery decisions for an integrated system with multi-item and partial scrap items, and on the optimal run time for a system with machine breakdowns (AR-policy) and scrap.Two mathematical models are developed respectively: (1) model 1 considers multi-item that deliver to single buyer under common cycle policy in a supply chain environment, which has two decision variables (T*, n*); (2) model 2 examines random machine breakdown situation (under AR-policy) with scrap and multi-deliveries, which has single decision variable (t1*). Numerical examples with sensitivity analyses are provided to verify the research results.

碩士
朝陽科技大學
企業管理系碩士班
96
This research considers imperfect quality product system whether rework on product policy to analyze and cost efficiency.One of the unrealistic assumptions of classic Economic Production Quantity(EPQ)model is that it assumes manufacturing facility functions perfectly at all times.However,in most practical settings,due to process deterioration or other factors,defective items are generated.The imperfect quality items can fall into two groups,the repairable and the scrap.Sometimes,the imperfect quality items can be reworked and repaired with additional repairing and holding costs. Two specific models are considered for different inventory situations in this research.They are situations where：(1)the imperfect quality system in an EPQ model with backlogging permitted, and all defective items are reworked and can be repaired;(2)the imperfect quality system in an EPQ model with backlogging permitted, and all defective items are scrap.Under the situations that have already known,this research proposes a mathematics judgment type on EPQ model with scrap and rework defective items and derived the optimal inventory product model and backordering level that minimize overall production costs.Numerical example is provided to demonstrate their practical usages.

碩士
朝陽科技大學
工業工程與管理系
103
This study determining the production cycle and delivery strategy for manufacture-customer integrated system with (n+1) distribution plan, scrap, breakdown and two-stage multi-item production system with delayed product differentiation . Assuming the machine will be breakdown randomly in a single production process and using AR (abort / resume) as a machine handling method. At single product and multi-item products in the production process, there will be output the defective products, and all the defective products are scrapped. Traditional EPQ model only optimize manufacturer but nowaday the situation is different . To be more consistent with the actual manufacturing of production, this study extend the traditional EPQ(Economic Production Quantity) model to integrating the production side and the customer supply chain systems. This study will establish the mathematical model according to the above assumptions. This study according to the above assumption that established two mathematical models：Model (1) discuss (n+1) distribution plan and integrate the manufacturer and the customer supply chain to determine the optimal production cycle, and the analysis and comparison. Model (2) discuss the optimal production cycle and delivery times under the different production program, delayed product differentiation of multi-items with imperfect of two-stage production and multi-delivery policy. Finally, numerical example with sensitivity analyses for two models. Expectations of mathematical models of this study can be used as a decision basis for practical reference.

碩士
朝陽科技大學
工業工程與管理系碩士班
99
This research develops two mathematical models with buyer’s inventory holding costs under the imperfect production system. They are (1) EPQ model with (n+1) deliveries strategy to multiple-buyers. This model also assumes have failure ratio in rework of defective items. (2) Multi-item production system with scrap and multi-delivery policy under rotation cycle policy. Traditional EPQ model assumes that the demand for the shipment is continuous, but it is not realistic. Therefore, the delivery of products often adopts multiple fixed quantity shipments. Total costs include manufacturer and buyer of inventory costs, and the objective is to minimize the total costs. Optimal lot size and best delivery policy are derived for Model 1. Optimal production time and number of deliveries are obtained for Model 2. Finally, numerical examples are provided for validation and sensitivity analysis demonstrates its applicability.

碩士
中興大學
材料工程學系所
95
Because of magnesium alloys have low density and high specific strength, and shock absorption ability, Mg alloys has an increasing number of uses in automotive and aerospace and electronic consumer. When Mg products are in great demand for various applications, mass of end-of-life and post-consumed Mg products generated. However, only high-grade Mg scraps are recyclable and over half of all Mg scraps cannot be processed economically. This work proposes a new method for generating H2 gas in from waste metallic magnesium, catalyzed by a platinum-coated titanium net or 304 stainless steel net in 3.5 wt% aqueous NaCl by the hydrolysis of low-grade Mg alloy scraps. A Pt-coated Ti net or 304 stainless steel net was used to catalyze hydrolysis. Pt-coated Ti net and 304 stainless steel nets are reused. The Pt-coated Ti net was used five times, the generated H2 of average cumulative volume of 33.7 liter in 50 minutes. The 304 stainless steel nets was used five times, the generated H2 of average cumulative volume of 13.17 liter in 50 minutes. The hydrogen produced from magnesium scraps and oxygen obtained from cylinder, was fed to proton exchange membrane fuel cell (PEMFC) to produce electricity. High purity hydrogen has been produced from spontaneous chemical reaction without any environmental pollution.

博士
中興大學
材料工程學系所
95
Due to excellent properties such as high specific strength, excellent vibration damping property and good EMI (electromagnetic interference), Mg alloys has an increasingly number of uses in transportation vehicle (e.g., door frame, engineering covering, oil pan, wheel, etc.) and the outer shell of 3C electronic products (e.g., the upper cover and base seat of notebook computer, the outer covering of personal mobile communication tool, etc.). Recycling of Mg scraps (i.e., post-consumed or end-of-life Mg products) has become increasingly important. This study proposes a new method for generating H2 gas in aqueous NaCl by the hydrolysis of Mg scraps. The experimental findings of this study not only indicate a method for generating hydrogen but also promote the recycling of the Mg scraps. Pt-coated Ti net (i.e., ~ 2.5 μm of platinum film being electroplated on the surface of Ti net) was adopted as a catalyst to promote the hydrolytic reaction of an Mg sample in aqueous NaCl (5 wt.%) to generate H2 without extra supply of power. Two experiments were conducted and the volumes of H2 generated were compared. In one of the experiments, the Pt-coated Ti net was statically loaded on the top surface of the Mg sample, with a loading force of 6 ± 0.5 kg. In the other, the Pt-coated Ti net was ground against the surface of the Mg sample (6 ± 0.5 kg, 8 ± 1 rpm). When a Pt-coated Ti net was statically loaded (6 ± 0.5 kg) on the Mg sample, the average H2 generation rate of about 302.3 ml min-1(g of catalyst)-1 was measured. The curve of cumulative volume of generated H2 reached a plateau after the hydrolysis reaction proceeded a certain time. Mg(OH)2 passive layer which prevented contact between the catalyst (Pt/Ti net) and the Mg sample was the major reason leading to the plateau. When the Pt-coated Ti net was ground (6 ± 0.5 kg, 8 ± 1 rpm) onto the Mg sample surface, more H2 gas was produced than was generated by static loading. The cumulative volume of H2 gas generated was almost linearly proportional to the reaction time. The average H2 generation rate was calculated to be 432.4 ml min-1(g of catalyst)-1. No Mg(OH)2 passive layer formed on the Mg sample surface, because the Pt-coated Ti net ground against the sample, removing the Mg(OH)2 layer. A little of the Pt had been consumed (~ 0.0278 g). The generated gas was analyzed by GC (gas chromatography). Only hydrogen and water vapor were detected. The purity of the hydrogen was analyzed to be around ~ 97.2 % mole fraction. Additionally, the maximum volume of generated H2 was observed in 3.5 wt.% aqueous NaCl. In order to improve the H2 generation efficiency of the Mg scraps, platinum-coated Ti (Pt-Ti) net and AISI 304 stainless steel (S.S.) net were dipped in the semi-solid Mg scraps. The average cumulative volume of generated H2 in 3.5 wt.% NaCl solution at 25 ˚C using Mg scraps/Pt-Ti samples and Mg scraps/S.S. samples was about 28.2 ± 5.7 liter and 16.1 ± 7.8 liter. The generated H2 volume per one gram of Mg scraps consumption was 1.0 ± 0.1 liters from Mg scraps/Pt-Ti samples, which was similar to the result by using Mg scraps/S.S. samples (1.1 ± 0.1 liters). In addition, both of these two metallic net catalysts showed a good durability of more than 5 experimental cycles to be re-used for H2 generation. The generated H2 in this study was converted into the electrical energy by fuel cell. A set of used Pt-coated Ti nets (20 pieces, the 4th time of use) was applied to be the catalyst metal, the cumulative H2 volume was about 11.3 liters in 50 min. The power generated was about 1.79 MJ (498.1 Wh) during the H2 generation. New AISI 304 stainless steel nets (20 pieces) were used as the catalyst. The cumulative H2 volume within 50 min was about 10.4 liters. The generation of power was about 1.53 MJ (424.4 Wh). The systematic analytical method of life cycle assessment (LCA) was carried out to investigate the environmental impacts of proposed H2 production process. The H2 production processes from metallic materials (i.e., Al powders, Mg powders) and the recycling process of Mg scraps were considered for comparison with LCA method. The energy requirement using Mg scraps/Pt-Ti couples to generate 1 kg of H2 was about 35.1 MJ. Around 34.9 MJ was needed by applying Mg scraps/S.S. couples to produce 1 kg of H2. The main energy consumption resulted from the preparation of Mg scraps/Pt-Ti and Mg scraps/S.S. couples. Moreover, the energy requirement of 1 kg H2 production by Al and Mg powders was about 11804 MJ and 6240 MJ. The energy requirements for generating 1 kg of H2 are mainly because of the energy being consumed to prepare the metallic powders. In addition, the energy requirement for producing 1 kg H2 by electrolysis water method (235 MJ or 243 MJ) was much higher than that of present study. Also, the H2 production process by this method, the air pollutants such as CO2, SO2 and NOx was released. From the viewpoint of recycling process of Mg scraps, the energy requirement and pollutant released of present study and conventional process were compared. The proposed process in present study for the recycle of 1 kg Mg scraps was about 2.9 MJ. The energy requirement for recycling 1 kg Mg scraps is about 151 MJ or 164 MJ in conventional processes.